A conventional light-emitting chip or light-emitting diode (LED) with layout of gold wires and electrodes is used as a light source or illumination device. The LED is widely applied to various sites or environments. In conventional technique, a light-emitting module is often used to project white light onto an exhibited environment or product. The light-emitting module includes blue light LED. The light emitted from the blue light LED energizes yellow fluorescent powder or phosphor to produce white light. Also, red, blue and green LED can be combined into a white light emitting module. For example, US 2007/0284563 A1 discloses a light emitting device including RGB light emitting diodes and phosphor. U.S. Pat. No. 8,008,850 B2 discloses a color temperature tunable white light emitting device, (that is, Taiwanese Patent No. 98125802 “color temperature tunable white light emitting device”).
In U.S. Pat. No. 8,008,850 B2, in order to achieve better light output effect, on the LED are arranged components of reflection plate, air medium layer, laminated universal reflector with a refractivity larger than that of the air medium layer, transparent substrate and light diffusion plate. Therefore, the light emitting device has a relatively complicated structure. Also, the manufacturing time of the light emitting device is longer and the manufacturing cost is higher. This is not what we expect.
In conventional technique, in order to achieve better white light rendering index, a wavelength conversion material (such as fluorescent powder or phosphor with a wavelength ranging from 500 nm to 780 nm) is disposed on blue light LED with a wavelength ranging from 440 nm to 460 nm. The wavelength conversion material serves to convert the light emitted from the blue light LED into colored light of green to red. The colored light is mixed with the light emitted from a deep blue light LED with a light wavelength ranging from 400 nm to 440 nm to achieve a pure white light output effect. For example, WO 2013/150470 A1 discloses a white light emitting module.
WO 2013/150470 A1 is characterized in that the wavelength conversion material serves to convert the light emitted from the blue light LED into colored light of green to red. The colored light is mixed with the deep blue light emitted from a deep blue light LED with a certain wavelength or short wavelength to achieve a white output light. The light of the deep blue light LED is not converted by the wavelength conversion material to change the wavelength. In addition, the light of the deep blue light LED is not a normal blue light so that the light emitting module can output pure white light.
It is tried by the applicant to provide a light-emitting device in which the assembly of the components is redesigned in use form and structure to distinguish the light-emitting device from the conventional technique and improve the application thereof. The light-emitting device is able to enhance the white light rendering effect and project white light onto a specific product in an exhibition site or other environment. Also, the light-emitting device of the present invention overcomes the problems of the conventional technique that the structure is complicated, the manufacturing time is longer and the manufacturing cost is higher.